There are a wide variety of handheld lamps on the market. For instance R.O.C. patent Nos. M299254 entitled “Flashlight”, M297430 entitled “Flashlight” and M290205 entitled “Multifunctional structure for flashlights to provide versatile light” generally have a barrel case to house a power supply and a switch circuit, and at least one lamp bulb at a front end to form a portable flashlight to facilitate carrying. The flashlights thus formed have the light converging at the front side. They mostly focus on improvements of the style, function and light intensity, but do not provide a structure to alter light projection. Hence they mostly have the light focusing in one direction. Camping lamp is another type of portable lighting feature to provide light projection for a greater area during camping outdoors. Its light projects outwards transversely to illuminate the surrounding environment of the lamp. It projects light in directions different from the conventional flashlights. To go outdoors for travel or doing recreational activities has to carry two sets of lamps. They occupy a lot of space and incur great inconvenience. The present invention aims to provide an improved handheld lamp that can alter light projecting direction to meet requirements of different environments.